The purpose of this proposal is to identify and quantitate lectin receptors on human corneal endothelial cells and compare differences between these cells, which are unable to undergo significant mitosis, and rabbit corneal endothelial cells which by contrast, have a high mitotic capacity. Established techniques will be used to grow rabbit and human corneal endothelial cells in tissue culture. A group of four to six well characterized lectins will be iodinated by the chloramine-T procedure and will be used as ligands in the binding assays to identify their receptors in the above cells. Scatchard plot analysis will be used to estimate the number of binding sites of various lectins on human and rabbit corneal endothelial cells. Since lectins bind to specific sugar residues and are too large to penetrate the interior of the cells, this study should indicate whether these two types of cells differ in their membrane glycoconjugates. Since plasma membrane glycoconjugates have been implicated in the control of mitosis, this investigation may contibute to our understanding of the high mitotic capacity of rabbit corneal endothelim and could serve to partially explain the almost non-existent mitotic ability of the human corneal endothelium in vivo. Information derived from such studies could lead us eventually to manipulate the conditions which may enable the human corneal endothelium to undergo mitosis.